What was noticable about the C code was that there was no license attached; this means that the implementation fall under default copyright laws (in this case, US laws). As such, any type of modification or derivative (which the C++ implementation might be considered as) is most likely not directly allowed.

I sent an e-mail to the authors to rectify the situation and make sure there is sound lawful ground for DC++, other derivatives and users of the C++ code.